Grinding wheel



FIG. 1 is a front view of a grinding wheel showing my new design.

FIG. 2 is a rear view thereof.

FIG. 3 is a top view thereof.

FIG. 4 is a bottom view thereof.

FIG. 5 is a side view thereof.

FIG. 6 is a sectional view, taken in the direction of the arrows on the line VI--VI of FIG. 1. 

The ornamental design for a grinding wheel, as shown and described. 